Keep in mind that 65 W desktop quad-cores are of somewhat similar price to mobile dual-cores of similar GHz. And multi-threading is getting more and more important.The low-power Core 2 Quads are fine, but in single-threaded applications (i.e. what most iMac users will use) they will be beaten by higher-clocked dual core chips.
2.27 GHz and 2.53 GHz are also available (for higher prices).The current notebook Core 2 Quad, the x9000, is only 2.0Ghz - again, it would be much slower, for most users, than a much higher-clocked dual core.
And what's wrong with Apple giving an OPTION for quad-core? Instead we have this "GHz Rule" where Apple won't allow higher-clocked dual-cores in the same lineup with lower-clocked quad-cores. Even if the quad-core would be better for some/many.
The presence of quad-cores on even cheap PCs? If you wanted to go the 65 W dual-core, then you can get 3.33 GHz cheaply (compared to mobile).Blame Intel, blame the form factor, but this isn't really Apple's problem. Plus, what's wrong with a 3Ghz Core 2 Duo? I think there's a lot of specification obsession going on here.